Utility loaders controlled by a stand-on or walk-behind operator (such loaders being referred to herein as “SOWB loaders”) are known for performing various types of work in an outdoor environment. While able to perform the types of work often associated with large skid steer loaders, SOWB loaders are generally smaller in size. Moreover, SOWB loaders do not carry an operator in a seated position as do larger skid steer loaders. Instead, they are most often operated by an operator who stands on a platform attached to the rear of the loader or, alternatively, walks on the ground behind the loader.
SOWB loaders typically employ a differential drive and steering system in which drive members (e.g., wheels or tracks) on opposite (left and right) sides of the loader may be driven at different speeds and/or in opposite directions. When the drive members are driven at different speeds and in the same direction, the loader will execute a turn towards the side of the slowest drive member. When the drive members are driven at the same speed but in opposite directions, the loader will execute a very sharp spin or zero radius turn about a vertical axis located between the drive members. This is accomplished using separate traction drives (e.g., individual hydrostatic transmissions) to independently power the left and right drive members. Dual traction or drive control levers are often used to independently control the traction drives. These control levers are pivotal in fore-and-aft directions from a neutral position in which the traction drives are unpowered and the loader is stationary. When the levers are equally pushed forwardly from neutral, the loader will move forwardly in a straight line at a speed proportional to the distance that the levers have been moved. Similarly, when the levers are equally pulled rearwardly from neutral, the loader will move rearwardly in a straight line at a speed proportional to the distance that the levers have been moved rearwardly. Again, by independently moving the two control levers, turns of varying degrees may be accommodated.
Modern SOWB loaders are able to accept a variety of working tool attachments that attach to a boom extending from a frame of the loader. The boom is typically formed by one or more lift arms that extend forward from the loader and include a mounting structure capable of receiving and supporting the attachment. The lift arms are typically pivotally attached to the loader and, via an actuator such as one or more hydraulic cylinders, may be pivoted relative to the loader such that the elevation of the attachment may be varied. In some loaders, the mounting structure may also pivot, relative to the lift arms, to adjust the orientation of the attachment relative to the lift arms.
While effective for their intended purpose, SOWB loaders are sometimes constrained in operation by their size and, in particular, by the limited reach of the lift arms.